Analog guys take the heat at Intel forum

Analog guys take the heat at Intel forum
The Intel Developer Forum (IDF) has become a pretty good place to scope out some analog product trends, particularly in PC temperature sensing and control. In a server environment, PC health monitors read both the operating temperature of the Pentium CPU and the ambient of the enclosure. If the system is running too hot, the health monitor can throttle back the Pentium clock-or turn up the fan speed via a pulsewidth modulation output.

At IDF, Analog Devices Inc. and National Semiconductor were across the aisle from each other, demonstrating competing temperature and control devices. ADI had a larger array of devices-some for temperature and fan control, with embedded E2PROM for threshold setting, and others controlling speeds for up to eight fans.

Paul Errico, ADI's marketing manager for thermal management products, seemed to believe that National's LM87 (demonstrated at IDF) was a second source for his own ADM1024. But National's data sheet for the three-input temp sensor and fan controller seemed to suggest something different. The device uses less than 10 microamps of current (5 microamps typical) and is accurate to within plus/minus 0.33 degrees C. ADI's most accurate reader is to within 1 degrees C.

Getting the heat out is a big issue for new-generation Pentiums. Earlier this year, at the International Solid-State Circuits Conference, Intel chief technology officer Pat Gelsinger called attention to the dramatic increases in power consumption and power density wrought by new-generation Pentiums. If current trends continue, you would have a heat generator with the intensity of a nuclear reactor, he said. Even employing 0.1-micron technology, a 425-million-transistor die, clocked at 30 GHz, would dissipate 3,000 to 5,000 watts.

Exhibitor Incep Technologies (San Diego) demonstrated a packaging concept at IDF that might help. Incep sandwiches the IA-64 voltage regulator module between the microprocessor substrate and the heat sink. Screw-type coaxial feedthroughs are used to transfer current from the power output transistors of the voltage regulator to the microprocessor. The package also guards against electromagnetic interference.

The Incep sandwich provides a low-inductance interconnect and supports (at 1-volt operating voltage) 100-A peak currents and 300-A/microseconds slew rates.